Answer:
Step-by-step explanation:
vertex of g(x) is (0, 0), so:
[tex]g(x)=a(x-0)^2+0\\\\g(x)=ax^2 \qquad and\qquad (2,\,1)\in g(x)\\\\1=a\cdot2^2\\1=4a\\a=\frac14\\\\g(x)=\frac14x^2=(\frac12x)^2[/tex]